The three-dimensional (3D) graphics is widely used in multimedia applications such as virtual world, video games, and so on. The three-dimensional graphics is usually represented with the three-dimensional model, and the mesh model is a commonly used three-dimensional model. In general, the mesh data for describing a mesh model is of enormous amount of data. In the Internet-based 3D graphics applications, it is often needed to transmit large amount of mesh data from a source computer (e.g., server) to a target computer (e.g., client) via the network. In the case of limited network bandwidth resources, if the amount of mesh data to be sent from the source computer to the target computer is large, it is likely that the mesh data can not be delivered in a timely manner, resulting in the corresponding 3D graphics being unable to be shown timely, which has adverse impacts on the user experience. Multimedia user may wish that, even in the case of limited bandwidth resources, the mesh data can be transmitted through computer networks at a satisfactory speed.
In the prior art there is a method for progressively transmitting the mesh model data. For example, in a paper “Progressive Mesh” (H. Hoppe, ACM SIGGRAPH 1996 Proceedings), there is a proposed method for transmitting the 3D mesh model. According to the method, 3D mesh models are converted into hierarchical meshes which are stored in the server. A hierarchical mesh comprises a number of sub-meshes. The sub-meshes each contain a part of information on the 3D mesh models and vary in the amount of information. Through the transmission of each sub-mesh, the data for the 3D mesh model is gradually transmitted to the receiving side. The receiving side, upon receiving the information of the sub-mesh, will display the corresponding three-dimensional graphics. Over time, the three-dimensional graphics displayed at the receiving side is getting closer and closer to the original 3D mesh model, until they become identical. The above-described method of the prior art, in the transmission of sub-meshes, is required to simultaneously transmit both the vertex data and the edge data for the original 3D mesh model.